Last Thursday I travelled to London to attend a course on critical appraisal run by the BMA. The course was introductory, and intended for audiences from different backgrounds, although as it happened, apart from a sole physical therapist, the other attendees were all librarians, which gave the discussion a particular focus.
Critical appraisal is a way of approaching published medical research in order to assess its reliability, accuracy and applicability in a wider context. Skilled critical appraisers know exactly what to look for in a study – whether the stats add up, whether the study design was appropriate, whether a randomised controlled trial was truly randomised, whether its findings could be applied to other contexts, and so on. In other words, at its most basic level, an understanding of the principles of critical appraisal should be enough to stop journalists writing articles about sausages causing cancer and the like. Health care workers need to understand critical appraisal in order to determine if the findings of a study should influence changes in their own day-to-day practice at work. As for me, I need to understand critical appraisal as it forms part of the series of training sessions my library runs for its users, and at some point I will have to teach it myself.
The course ran over an entire day, with the morning focusing on reading and then discussing as a group an article about a randomised controlled trial, and the afternoon involving the same, but using a systematic review as the discussion article. We worked with the CASP checklists, as they formed a useful structure for novice critical appraisers, pointing us to the relevant sections of the articles so that we could quickly find the information we needed. Our trainer stressed that we should not rely solely on the checklists, and that as we became more confident, it would be better to do away with them, as they can be a bit of a crutch. However, given that I am not going to be critically appraising articles on my own, but rather helping others to do so, I feel I should be using checklists as the first port of call for my students, at least until they have gained greater experience in critical appraisal.
Of particular value to me was the emphasis on statistics. I now understand the difference between absolute risk reduction and relative risk, and how to calculate these. It sounds basic, but I also now know to hone in on the numbers of participants listed in a study, and to check that all are accounted for – in other words, if the number of participants in the study is less at the end of the study than at the beginning, where did the ‘missing’ participants go? For someone with a background in humanities, and who finds tables of statistics opaque and daunting, these tips are really helpful in boosting my confidence in my ability to understand medical literature and help others understand it.
The course is fairly pricey, but if you are able to afford it or get funding from your institution to attend, I would really recommend it. I strongly encourage anyone working in an academic or medical library to attend.